The present invention relates to articles which absorb and/or contain bodily exudates, including disposable absorbent articles such as diapers, adult incontinence products, sanitary napkins and the like. More particularly, the invention relates to disposable absorbent articles including one or more reducing agents which act to modify the physical properties of feces or other bodily wastes which may be deposited in the article.
The major function of absorbent articles such as diapers and adult incontinence briefs is to prevent body exudates from soiling, wetting, or otherwise contaminating clothing or other articles, such as bedding, that may come in contact with the wearer. In recent years, disposable diapers, such as those disclosed in U.S. Pat. No. 5,151,092 issued to Buell et al., have become very popular and have generally replaced durable cloth absorbent articles because of their convenience and reliability. However, despite the effectiveness of such disposable absorbent articles, body exudates often still leak or are stored in the diaper such that the exudates soil and/or irritate the skin of the wearer. Additionally, body exudates often adhere aggressively to skin, increasing the difficulty of cleaning and increasing the likelihood of chronic residual contamination. The fundamental causes of these, and other key problems with absorbent articles of the art lie in the high viscosity of feces and the tenacity with which they hold their constituent water. These factors greatly inhibit the absorption of feces by conventional absorbent articles.
The undesirable effects of leakage and/or improper containment, difficult cleanup, and/or residual skin contamination are especially evident with regard to fecal matter deposited in the diaper. Feces contained in the diaper can harm the skin of the wearer over time and feces leaking from the diaper almost invariably presents unpleasant, messy clean-ups. Thus, several attempts have been made to add features to diapers such as barriers, pockets, spacers, transverse barriers, apertured topsheets and the like to limit the movement of the fecal material across the topsheet and/or to better confine the fecal matter in the diaper. However, such attempts have been generally unsuccessful because they fail to address the fundamental causes of these problems (i.e., the properties of feces) and, because of their cost and complexity. Further, many of the means for isolating or containing feces are directed to fecal material with certain physical properties (e.g., viscosity, free water content and particle size) and are not effective with exudates with physical properties outside a very small range.
Chemical agents have been employed in superabsorbent polymer particles to attempt to increase the osmotic potential of the polymer for purposes of increasing the effective capacity of the superabsorbent for urine. For example, EP 0420248 A1 describes the use of osmotic materials encased in chambers inside superabsorbent polymer particles to increase absorptive capacity. In such cases, however, the osmotic material is not available to contact any surrounding fecal material and thus, does not function as a feces modification agent as described herein.
U.S. Pat. No. 4,556,560 teaches the use of certain metal salts as lipase inhibitors. These agents are affixed to the topsheet via deposition using a volatile solvent. As taught, a urine voiding is required to wet the topsheet and release the lipase inhibiting agent. Also, the lipase inhibitors may be washed into the absorbent core as part of the urine gush. These factors clearly limit the accessibility of the agent by the fecal material.
U.S. Pat. No. 4,790,836 discloses a diaper including layer of medicated powder located between the absorbent core and a water-soluble film. The medicated powder is used to promote drying of the infant""s skin after the wearer wets the diaper. However, as shown in Table II, below, the embodiments disclosed in this patent do not function to provide the feces modification benefit of the present invention.
Accordingly, it would be desirable to provide an absorbent article with improved feces management properties. Further, it would be advantageous to provide an economical disposable article with the ability to minimize the negative effects of feces or other viscous bodily waste on the wearer or the caregiver. It would also be advantageous to provide an article which is designed to chemically or physically interact with the feces and to change the properties of the feces in order to improve acceptance of feces into the article and/or immobilization of the feces within the article and/or reduce the contamination of the wearer""s skin with feces. Also, it would be desirable to provide an article having sufficient effective capacity and retention capability to store the physically or chemically modified feces safely and cleanly away from the wearer""s skin and/or clothing throughout the expected time of use.
In order to help resolve at least some of the problems described above and otherwise found in the absorbent articles of the prior art, the present invention provides an article including a reducing agent which is available in an effective concentration to physically or chemically modify some or all of the fecal material or other bodily exudates deposited in the article. The modification of the feces may improve acceptance and/or retention of the exudates within the article to reduce the spreading of fecal material within the diaper and/or to reduce the tendency of the fecal material to adhere to the wearer""s skin. The present invention also provides an absorbent article capable of accepting, storing and/or immobilizing the exudates in their modified form to reduce the likelihood that the waste will migrate back toward the wearer""s skin once the waste is imbibed by the article. Accordingly, the absorbent article of the present invention may reduce the likelihood of harm to the wearer""s skin and/or the inconvenience to the caregiver normally associated with bowel movements.